Usually beginners are tearing ass to get at least some kind of contract. So do not even expect that the client write itself. If you are not steep with good experience upwork out on a rare topic.
At sufficiently pumped profile customers write quite actively. But usually written by those who need a permanent employee, ie they are looking for a good man for the long haul. For small tasks the clients themselves rarely write, unless I can do a mass mailing, but in this case, they are still rarely respond.